1. Field of the Invention
The present invention is directed to iontophoretic drug delivery systems, and more particularly to the interface structure between a power source and an electrode assembly.
2. Background Art
The use of iontophoretic drug delivery systems has been known in the art for several years. Such devices are generally used to deliver a drug to a patient through the patient""s skin or through the patient""s eye. Generally, such devices comprise an electrode assembly/patch and a power source/control module which is attached to the electrode assembly. Unfortunately, the attachment interface between the power source/control module and the electrode assembly suffers from some drawbacks.
Specifically, the interface structures commonly include an interface on both the electrode assembly and the power source, wherein one interface is matingly inserted into the other. Once mated, electrical contacts associated with the power source contact leads associated with the electrode assembly. Currently, because the interfaces engage in only one indexed position, the two interfaces must be substantially aligned before operative engagement therebetween. In addition, even when positioned in the proper indexed orientation, the actual xe2x80x9cnestedxe2x80x9d engagement requires more effort than necessary.
Another problem with the prior art devices is that once the interface structures are mated, it can be difficult to maintain good electrical continuity between the contacts of the power source and the leads of the electrode assembly. While various complex structures have been proposed, it has been difficult to find a solution which requires few components, is cost effective and which is reliable for the user.
It is thus an object of the present invention to provide an interface structure which facilitates attachment between the power source and the electrode assembly of an iontophoretic drug delivery device.
It is likewise an object of the present invention to provide an interface structure which effectively maintains electrical continuity between the power source and the electrode assembly.
These and other objects of the present invention will become apparent in light of the present specification, drawings and claims appended hereto.
The present invention is directed to an iontophoretic drug delivery apparatus. The apparatus comprises an electrode assembly, a power source and means for facilitating mating engagement therebetween. The electrode assembly includes a first interface and two electrical leads and the power source includes a second interface and two electrical contacts. The facilitating means enables mating engagement of one of the first and second interfaces into the other of the first and second interfaces with limited need for pre-alignment therebetween. In turn, the two electrical leads of the electrode assembly are oriented into secured/locked abutment with the two electrical contacts of the power source.
In a preferred embodiment of the invention, the facilitating means comprises a tapering structure associated with the outer surface of one of the first and second interfaces, and, an outwardly expanding structure associated with the other of the first and second interfaces. The positioning of the tapering structure toward and into the outwardly expanding structure slidably enables mating engagement between the first interface and the second interface.
In such a preferred embodiment, the tapering structure and the outwardly expanding structure each comprise corresponding conical configurations. Such conical configurations can have either a uniform or non-uniform geometry.
In another preferred embodiment, the facilitating means may further include means for rotatively positioning one of the first and second interfaces into desired alignment with the other. For example, the desired alignment may be in at least any one of two predetermined angular orientations.
In a preferred embodiment, the rotative positioning means comprises both of the first and second interfaces having elongated, substantially eliptical cross-sections.
In yet another preferred embodiment, the apparatus includes means for retaining the first and second interface in a desired mated engagement. In one such preferred embodiment, the retaining means may comprise at least one detent associated with one of the first and second interface, and, at least one biased tab associated with the other of the first and second interface. The biased tab lockably cooperates with an associated detent upon positioning of the first and second interface into a mated orientation.
In still another preferred embodiment, the apparatus may include means for biasing the leads of the electrode assembly with the electrical contacts of the power supply upon mating engagement therebetween. In one such embodiment, the biasing means may comprise an elastically deformable material associated with the leads. The elastically deformable material is associated with the first interface such that, upon mating engagement of the first and second interface, the contacts of the second interface elastically deform the material, which, in turn, biases the leads into electrical connection with the contacts.
In yet another preferred embodiment, the apparatus may further include a seal member (such as an O-ring) associated with one or both of the first and second interfaces. The seal member seals the underside of the power source from undesired contamination, such as moisture.
The invention may further include means for electrically connecting the two electrical leads with the electrical contacts in any one of at least two orientations. Preferably, the orientations are achieved by rotating either the electrode assembly or the power source, relative to the other, about an axis. In turn, the electrical connecting means comprises the positioning of an electrical lead of the electrode assembly and one of the two electrical contacts of the power source about a common axis of rotation.
In such a preferred embodiment, a second electrical contact is spaced apart from the axis of rotation a predetermined distance, and a second electrical lead is likewise positioned a predetermined distance apart from the axis of rotation. The second electrical lead is positioned so that the second electrical contact engages the second electrical lead in any of the at least two orientations.
In another preferred embodiment, the first orientation and the second orientation are separated by an angular distance of about 180 degrees.